Pressure vessel construction



May 21, 1957 E. E. scHoEssow PRESSURE VESSEL CONSTRUCTION Filed Nov. 22,1954 2 INVENTO R fr] 'oassow ATTORNEY FIG.2

United States Patent'O PRESSURE VESSEL CONSTRUCTION Earl E. Schoessow,Barberton,

Babcock & Wilcox Company, corporation of New Jersey Ohio, assignor toThe New York, N. Y., a

This invention relates to a pressure vessel construction having alaminated support skirt.

Pressure vessels of circular cross section are often supported by acylindrically shaped skirt support on a xed foundation. In such aconstruction there may exist large -dilerences between the temperatureof the shell and of the foundation, thus subjecting the skirt to alongitudinal temperature gradient. Such temperature conditions willcause the higher temperature portions of the skirt to expand to adiameter proportional to the thermal coeiiicient of expansion of themetal, and this diameter is different at all of the longitudinalpositions of the skirt. This induces longitudinal bending stresses intothe metal of the skirt. If the mechanical integrity of the skirt is tobe maintained under any given conditions of longitudinal temperaturegradient, these bending stresses must be at `a safe value, and suchvalue must be well within the elastic limit of the metal. The skirt isusually required to sustain the dead weight loading of the pressurevessel, the dynamic or shock loading of the vessel and the pipingreactions transmitted to it through the vessel. In many of the advancedengineering applications in use by industry today, the skirts arerequired to sustain very high temperature gradients, shock loads, andpiping reactions and the problem of obtaining a proper skirt design iscompounded when there is added the usual condition that the vessel andits support means must occupy a minimum volume. In this case theconventional skirt design, wherein the skirt is made of a single thickplate, becomes inadequate because the bending stresses are prohibitivelyhigh.

The present invention solves this problem by providing a cylindricallyshaped skirt support made of a number of thin shells placedconcentrically and coextensively one within another so as to present alaminated structure. For 'any given temperature conditions thisstructure is subject to much lower bending stresses than a solid plateof the same thickness. It is well known in the field of mechanics thatfor any given length of a member subjected to longitudinal temperaturegradient, that a thin member will develop less bending stress than athicker member. However, such thin sections will not carry as large acompressive load as thick members. The present invention involves anumber of thin members placed to gether in a laminated structure yandthus acting in conjunction to :carry the required compressive load withthe result that the composite structure develops less bending stressthan a single plate of the same dimensions. Thus there is provided ahigh temperature pressure vessel construction facilitating its supportwith a minimum of thermally created stresses.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and speciiic objects attained by its use,reference should be had to the accompanying drawings and descrip-2,792,965 Patented May 21, 1957 ICC tive matter in which there isillustrated and described preferred embodiments ofthe invention.

In the drawings:

Fig. 1 is a partial sectional elevation of a pressure vessel supportedby a laminated skirt in accordance with the invention;

Fig. 2 is a plan section on line 2 2 of Fig. 1;

Fig. 3 is a partial section of the lamina weld; and

Fig. 4 is a partial section of an alternate attachment of the skirt toafoundation.

A high temperature and high pressure vessel 10 having a closed end 11 issupported by a cylindrically shaped skirt 12 which rests on a foundation14. The lower end of the skirt 12 is fixed to the foundation 14 by anumber of circumferentially spaced angle irons 16..

The skirt 12 comprises the thin'lamina plates 18, 20 and 22. The innerplate 18 is formed from a rectangular plate into a circular shell andits edges joined by the longitudinal weld 24. The second plate 20, issimilarly formed into a circular shell and snugly fitted around plate 18with its longitudinal ends joined by a weld 26. Similarly the outsideplate 22 is formed into a circular shell and snugly tted around plate 20and its edges joined by the longitudinal weld 28. Each of 'thelongitudinal welds are made as in Figure 3 where the edges of the plate22 `are shaped to receive a backing strip 29. This c0nstructionprecludes any of the plates from being joined by the welds. The skirt isthen attached to the pressure vessel 10 by a large weld 30 which unitesall of the plates 18, 20 and 22 to the pressure vessel.

Fig. 4 is an alternate construction to that of Fig. l for attaching thelower edge of the skirt 12 to a founda tion 14A by a common weld joiningthe plates 18A, 20A and 22A. Such a construction would be used in caseswhere the pressure vessel 10 would have a large overturning moment.

The lamination plates are assembled in such a way that they act inconjunction for supporting the vessel but are free to individually andindependently distort in bending. It is important that in the assemblyof the laminations that they not be preshunk into place or that they notbe joined at any point except at the ends of the skirt. They should besimply in surface to surface contact so as to give mutual support toeach other to withstand the compressive loading.

The present invention provides a support for a pressure vessel which isof the shortest longitudinal length for any given set of load andtemperature conditions.

While in accordance with the provisions of the statutes, I haveillustrated and described herein a speciic form of the invention nowknown to me, those skilled in the art will understand that changes maybe made in the form ot' the apparatus disclosed without departing fromthe spirit of the invention covered by my claims, and that certainfeatures of the invention may sometimes be used to advantage without acorresponding use of the other features.

I claim:

1. A high temperature pressure vessel construction comprising avertically elongated pressure vessel subject to a high temperature andhaving a circular horizontal cross section and a metallic laminatedcylindrically shaped skirt having its larninations integrally secured tothe pressure vessel and to each other by a common securement in heattransfer relationship and extending beyond one end of said vessel forthe support thereof.

2. A high temperature pressure vessel construction comprising avertically elongated pressure vessel subject to a high temperature andhaving a circular horizontal cross section and a metallic laminatedcylindrically shaped skirt secured to the pressure vessel in heattransfer relationship and extending beyond one end of said vessel forthe support thereof, said skirt formed by a plurality ofconcentric'metal laminac arrangedin surface to surface contact and joined to eachother only at their end portions and free for relativernovement'interrnediate their ends.

3. A high temperature pressure vessel construction comprising avertically elongated pressure vessel subject to a high temperature andhaving a circular horizontal Y cross section anda metallic laminatedcylindrically Ashaped skirt secured to the pressure vessel in heattransfer rela tionship 'and' extending beyond one end of said vessel forthe support thereof, said skirt formed'by a plurality of concentricVcoextensive metaly laminae arranged' in surface to surface contactandjoined to each other only at their end portions vandrfree forrelative movement intermediate their ends.

4. A high temperature pressure vessel construction comprising-avertically elongated'pressure vesselsubject to a high temperature -andhaving a -circular horizontal cross` section and a 'metallic laminatedcylindrically ShapedslCirt'secured-to'thepressure vessel in heattransfer relationship Vand'extencling*beyond one end kof said `vesselfor 'thesupport'thereoh said skirt formed Vby a plurality of concentricmetal laminae arranged in surface to sur-V fa-cefcontactand joined toeach other only'at their end portions, said laniinae being joined toeach other and to said 'vessel by a-comrnon Weld at one edge ofsaidskirt.

5; A high temperature `pressure vessel construction comprising avertically elongated pressure vessel subject to a high temperature andhaving acircular horizontal cross section and a metallic laminatedcylindrically shaped `skirty secured to the pressure vessel in heattransfer relationship and extending beyond one end of said vessel forthe support thereof, said skirt formed by a plurality of concentricmetal laininae arranged in surface to surface contact and joined to eachother only at their end portions, said laminae Being-joined to eachother and to the lower portion of said vessel by a common Weld at oneedge of said'ski'rt.

6. A high temperature pressure vessel construction comprising avertically elongated pressure vessel subject to a high temperature andhaving a circular horizontal cross section and a metallic laminatedcylindrically shaped skirt secured to the pressure vessel in heattransfer relationship .and extending beyond one end of said vessel forthe support thereof, said. shirt formed by a plurality of concentricmetal larninae arranged in surface to surface contact and joined to eachotheronly at their yend portions, said'laniinae being joined to eachother .and to the lower portion of said vessel and said foundationstructure by common Vweld's at opposite edges of said skirt.

References Cited in the ille of -lthis patent UNITED STATES PATENTS55,791, VanV Duzer .June 19, .1866 95,324 Cochran Sept. 28, 18691,921,247 Walker Aug. 8, 193,3 2,057,347 Reed Oct. 131936 2,404,777Gaines July 30, 1946

